add a stringify method to the Policy class (#253)

lib/Mail/DMARC/Policy.pm

@@ -56,6 +56,19 @@ sub parse {
     return bless \%policy, ref $self;    # inherited defaults + overrides
 }
 
+sub stringify {
+    my $self = shift;
+
+    my %dmarc_record = %{$self};
+    delete $dmarc_record{domain};
+
+    my $dmarc_txt = 'v=' . (delete $dmarc_record{v}); # "v" tag must be first
+    foreach my $key ( keys %dmarc_record ) {
+     $dmarc_txt .= "; $key=$dmarc_record{$key}";
+    }
+    return $dmarc_txt;
+}
+
 sub apply_defaults {
     my $self = shift;
 
@@ -269,6 +282,13 @@ via DNS.
     $pol->parse( 'v=DMARC1; p=none; rua=mailto:[email protected]' );
     $pol->parse( 'v=DMARC1' );       # external reporting record
 
+=head2 stringify
+
+Returns the textual representation of the DMARC record.
+
+    my $pol = Mail::DMARC::Policy->new('v=DMARC1; p=none;');
+    print $pol->stringify;
+
 =head1 Record Tags
 
 =head2 Tag Overview

t/01.Policy.t

@@ -25,6 +25,7 @@ stderr_is { test_parse() } $expected_parse_warning, 'STDERR yields parse warning
 test_setter_values();
 test_apply_defaults();
 test_is_valid();
+test_stringify();
 handles_common_record_errors();
 
 done_testing();
@@ -259,6 +260,11 @@ sub test_is_valid {
     ok( $pol && $pol->is_valid, "is_valid, pos, implicit p=none w/rua" );
 }
 
+sub test_stringify {
+    $pol = Mail::DMARC::Policy->new( 'v=DMARC1; p=reject' );
+    cmp_ok($pol->stringify, 'eq', 'v=DMARC1; p=reject');
+}
+
 sub handles_common_record_errors {
 
     foreach my $d (<DATA>) {